偏振復用相干光OFDM系統(tǒng)信道估計技術研究
發(fā)布時間：2019-06-15 14:49
【摘要】：目前100 Gb/s速率的光.通.信系.統(tǒng).已經(jīng)投入市場使用,當前研究重點放到了100Gb/s以上的光通信系統(tǒng)。高速光通信系統(tǒng)中應用了偏振復用技術,使用偏振復用技術大大降低了系統(tǒng)對于色度色散(Chromatic Dispersion,CD)、偏振模色散(Polarization Mode Dispersion,PMD)這一系列劣化損傷的容忍度,信道估計和解偏振復用越來越難以實現(xiàn)。隨著數(shù)字電路芯片制作工藝水平的提升,模數(shù)轉換器(Analog to Digital Converter,ADC)所需達到的采樣速率與光傳輸速率相匹配的要求逐步成為現(xiàn)實。利用相干光正交頻分復用(Coherent Optical Orthogonal Frequency Division Multiplexing,CO-OFDM)不僅能增大接收機靈敏度,而且能夠輔助數(shù)字信號處理(Digital Signal Processing,DSP)來抵抗光信道中的劣化,比如CD和PMD。在采用PDM-CO-OFDM技術的通信系統(tǒng)中的大部分DSP技術中,信道估計技術是其中非常重要的一門技術,是解偏振復用的首要任務。最小二乘(LS,Least Square)信道估計算法,是當前廣泛使用的信道估計算法,其算法復雜度低,但抗噪聲能力差,為了提高其精確度必須進行改進�，F(xiàn)有的信道沖擊響應(Channel Impluse Response,CIR)算法可以降低噪聲對LS算法的破壞,但是仍然存在一些缺陷。本文研究了偏振復用相干光正交頻分復用(Polarization Division Multiplexing Coherent Optical Orthogonal Frequency Division Multiplexing,PDM-CO-OFDM)傳輸系統(tǒng)。對信號和信道模型進行了分析,利用VPI Transmission MakerTM軟件搭建了200 Gb/s速率的PDM-CO-OFDM光傳輸仿真平臺。該傳輸平臺可光纖信道的劣化進行仿真,例如CD、PMD、激光器線寬、ASE噪聲等效應。利用VPI Transmission MakerTM以及MATLAB搭建了DSP算法仿真平臺,在此平臺上對現(xiàn)有的PDM-CO-OFDM光通信系統(tǒng)的信道估計算法進行了分析,并針對其局限性,提出了基于DFT算法的改進方案;此外,在PDM-CO-OFDM系統(tǒng)中引入了在圖像處理領域很常用的離散余弦變換(Discrete Cosine Transform,DCT)并對DCT算法進行了改進,在VPI+MATLAB平臺上得到了驗證。
[Abstract]:The current rate of light at 100 Gb/s. Pass. Department of Information. Unified It has been put into use in the market, and the current research focuses on the optical communication system above 100Gb/s. Polarization reuse technology is applied in high speed optical communication system, and polarization reuse technology is used to greatly reduce the tolerance of chromaticity dispersion (Chromatic Dispersion,CD) and polarization mode dispersion (Polarization Mode Dispersion,PMD) to a series of deterioration damage. It is more and more difficult to realize channel estimation and polarization reuse. With the improvement of the fabrication technology of digital circuit chip, the requirement of matching sampling rate and optical transmission rate of analog-to-digital converter (Analog to Digital Converter,ADC) has gradually become a reality. Coherent Optical orthogonal Frequency Division Multiplexing (Coherent Optical Orthogonal Frequency Division Multiplexing,CO-OFDM) can not only increase the sensitivity of the receiver, but also assist digital signal processing (Digital Signal Processing,DSP to resist deterioration in optical channels, such as CD and PMD.. In most of the communication systems based on PDM-CO-OFDM technology, channel estimation technology is one of the most important technologies, and it is the primary task of depolarization reuse. The least squares (LS,Least Square) channel estimation algorithm is a widely used channel estimation algorithm at present. Its complexity is low, but its anti-noise ability is poor. In order to improve its accuracy, it must be improved. The existing channel impulse response (Channel Impluse Response,CIR) algorithm can reduce the damage of noise to LS algorithm, but there are still some defects. In this paper, the polarization multiplex coherent optical orthogonal frequency division multiplexing (Polarization Division Multiplexing Coherent Optical Orthogonal Frequency Division Multiplexing,PDM-CO-OFDM) transmission system is studied. The signal and channel model are analyzed, and the PDM-CO-OFDM optical transmission simulation platform at 200 Gb/s rate is built by using VPI Transmission MakerTM software. The transmission platform can simulate the deterioration of fiber channel, such as CD,PMD, laser linewidth, ASE noise and so on. The DSP algorithm simulation platform is built by using VPI Transmission MakerTM and MATLAB. On this platform, the channel estimation algorithm of the existing PDM-CO-OFDM optical communication system is analyzed, and an improved scheme based on DFT algorithm is proposed according to its limitations. In addition, the discrete cosine transform (Discrete Cosine Transform,DCT), which is commonly used in image processing, is introduced into PDM-CO-OFDM system and the DCT algorithm is improved, which is verified on VPI MATLAB platform.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN929.1
本文編號：2500301
[Abstract]:The current rate of light at 100 Gb/s. Pass. Department of Information. Unified It has been put into use in the market, and the current research focuses on the optical communication system above 100Gb/s. Polarization reuse technology is applied in high speed optical communication system, and polarization reuse technology is used to greatly reduce the tolerance of chromaticity dispersion (Chromatic Dispersion,CD) and polarization mode dispersion (Polarization Mode Dispersion,PMD) to a series of deterioration damage. It is more and more difficult to realize channel estimation and polarization reuse. With the improvement of the fabrication technology of digital circuit chip, the requirement of matching sampling rate and optical transmission rate of analog-to-digital converter (Analog to Digital Converter,ADC) has gradually become a reality. Coherent Optical orthogonal Frequency Division Multiplexing (Coherent Optical Orthogonal Frequency Division Multiplexing,CO-OFDM) can not only increase the sensitivity of the receiver, but also assist digital signal processing (Digital Signal Processing,DSP to resist deterioration in optical channels, such as CD and PMD.. In most of the communication systems based on PDM-CO-OFDM technology, channel estimation technology is one of the most important technologies, and it is the primary task of depolarization reuse. The least squares (LS,Least Square) channel estimation algorithm is a widely used channel estimation algorithm at present. Its complexity is low, but its anti-noise ability is poor. In order to improve its accuracy, it must be improved. The existing channel impulse response (Channel Impluse Response,CIR) algorithm can reduce the damage of noise to LS algorithm, but there are still some defects. In this paper, the polarization multiplex coherent optical orthogonal frequency division multiplexing (Polarization Division Multiplexing Coherent Optical Orthogonal Frequency Division Multiplexing,PDM-CO-OFDM) transmission system is studied. The signal and channel model are analyzed, and the PDM-CO-OFDM optical transmission simulation platform at 200 Gb/s rate is built by using VPI Transmission MakerTM software. The transmission platform can simulate the deterioration of fiber channel, such as CD,PMD, laser linewidth, ASE noise and so on. The DSP algorithm simulation platform is built by using VPI Transmission MakerTM and MATLAB. On this platform, the channel estimation algorithm of the existing PDM-CO-OFDM optical communication system is analyzed, and an improved scheme based on DFT algorithm is proposed according to its limitations. In addition, the discrete cosine transform (Discrete Cosine Transform,DCT), which is commonly used in image processing, is introduced into PDM-CO-OFDM system and the DCT algorithm is improved, which is verified on VPI MATLAB platform.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN929.1
【參考文獻】
相關期刊論文 前1條
1 周一青,胡愛群;利用訓練幀進行OFDM系統(tǒng)同步的新算法[J];通信學報;2001年04期
，本文編號：2500301
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